Filter for liquids



Patented Mar. 2, 1954 2:.

UNITED PATENT 2,679,852 1 Fmrr:a FOIR L IDS Eric BrownDavidson, Winchfield, England nrfiat i -D eml 11, .9. 1l er aN -261 Claims, pri'ority, application .GreatBritain I k Di (!mb91 15, 1950 "Ifhisinvention is for improvements in or relating to filters for liquids, and more particularly. to an oil filter for usein connection with internal combustionengines of, the. diesel type and, has 'for its object the provision of a filter whichiis more simple and inexpensive than-"the filter at present employed;

According to the present invention there is provided a filter for liquids, for example, the fuel Oil-16f a diesel engine, which comprises in combination a support "in the form of a spiral spring provided with a sheath formed from a single wire which extends in the form of a spiral around adjacent turns of the spiral spring, the turns of the spiral wire which extend between any three turns of the spiral spring being arranged so that they alternate with one another on the intermediate turn of the three turns, and a filter material enveloping the cylindrical exterior of said support.

The invention will be more particularly described with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a support in the form of a spiral spring provided with a sheath for a filter material.

Figure 2 illustrates an oil filter constructed in accordance with the present invention.

Referring to Figure l of the drawings there is illustrated a support in the form of a spiral spring I upon which is threaded a flat spiral 2 formed from a single length of wire. In order to produce a support such as is illustrated in Figure 1 a predetermined number of convolutions of the fiat spiral 2 are threaded upon one free end of the spiral spring I, whereupon the following convolutions of the fiat spiral are threaded upon the free end of the spiral spring I so that they alternate with convolutions which have been already threaded upon the free end of the said spiral spring I. If this procedure is repeated there will eventually be produced a unit substantially of the configuration illustrated in Figure 1 and similar in construction to a unit in which a single wire is wound around each pair of adjacent turns of the spring in the direction of the longitudinal axis of the spiral spring I in such a manner as to ensure that the convolutions f the wire which extend between any two adjacent turns B and C of the spiral spring I alternate on the intermediate turn B of the three turns A, B and C with the convolutions which extend between the convolutions B and A. The flat spiral 2 so threaded, or a single wire so wound, will form a sheath on the exterior of the traversed by two, adjacent di lar o t a s o hespiralsnr n p et ably by shortening the lengths of the flat spiral 2 and twisting the ends of the wire of the flat sprial around the adjacent convolutions in the manner indicated at F and K of Figure 1.

The support hereinbefore described, has thereafter wound upon or suitably applied to the exterior surface thereof, a filter material 3 (Figure 2) which is arranged to envelop the support and is such as to permit oil to be forced in a radial direction towards the axis of the support through the filter material.

The filter unit hereinbefore described is adapted to be inserted into a filter chamber 4 so that it extends over a centrally disposed tube 5 which forms the outlet for the said chamber. Oil is admitted to the chamber 4 through the inlet 6.

When the filter unit is placed over the tube 5 it bears at its lower end upon a supporting plate I carried by the said tube 5 and a sealing member 8 of corresponding shape to the supporting plate 1 is placed over the upper free end of the filter unit whereupon a cover cap 9 is placed over the open end of the chamber 4. A nut I 0 is then screwed on the free end of the tube 5 so as to draw the cover cap 9 into fluid tight connection with the open end of the chamber 4. When the nut I0 is screwed home a spring ll extending between the nut l0 and the sealing member 8 serves to clamp the filter unit firmly in position between the supporting plate 1 and the sealing member 8.

Owing to the fact that the filter unit above described can be formed very simply and inexbecome exhausted, be discarded, and replaced by another complete filter unit, thus eliminating the expensive and dirty operation.

It will be appreciated that although the sup port hereinbefore referred to has been specifically described in connection with a flat spiral forming the sheath of the spiral spring, nevertheless the sheath can be formed of a curved spiral which will permit of a certain degree of radial displacement due to contraction or expansion of the filter material.

It will be understood that although the particular embodiment of the invention described with reference to the accompanying drawings is an oil filter, the same general principles as to construction and manner of operation would be applicable to filters for other liquids, for example, milk.

Thus it will be seen that according to the present invention there is provided a filter which is simple in its construction and, due to the fact that it can be inexpensively manufactured, avoids a considerable amount of manual labour, by reason of the fact that after the filter material has become exhausted the support, together with the filter material, may be discarded.

What I claim as my invention and desireto secure by Letters Patent of the United States is:

1. A filter for liquids which comprises in combination a support in the form of a spiral spring the turns of which are spaced, provided with a sheath formed from a single wire in the form of aspiral each turn of which extends'around two adjacent turns of the spring, the turns of the spiral wire which extend between any three turns of the spiral spring being arranged so as to alternate with one another on the intermediate turn of thethree turns, and a filter material enveloping the sheathed exterior of said support.

' 2. A filter as claimed in claim 1 in combination 4 1 with a chamber for the liquid having a centrally disposed tube comprising an outlet to said chamber arranged to receive said filter and hold the same between a supporting plate and a sealin member and means for admitting the liquid to said chamber and permitting the same to pass in a substantially radial direction through the said filter material into said outlet tube.

3. A filter as claimed in claim 2 wherein the filter material is held in close contact with the supporting plate and the sealing member by yielding pressure applied to the sealing member when the cover cap of the chamber is fixed in a fluid tight condition on the said chamber.

4. A filter as claimed in claim 3 wherein the supporting platerand the sealing member ensure that liquid passing from the inlet to the outlet of the chamber can only pass through the filter material in a direction transverse to the axial direction of the support. V

- 7 7 ERIC BROWN DAVIDSON.

1 References Citedin the file of this patent UNITEDSTAT'ES PATENTS um er ,7 name Date A 2,196,821 Arnold Apr. 9, 1940 1 FOREIGN PATENTS Number 7 Country Date Great Britain Mar. 14, 1929 

